EMPLOYEE BENEFIT PLANS (Details) - USD ($)	3 Months Ended		9 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Components of net periodic cost
Discretionary contribution			$ 30,000,000	$ 0
Pension [Member]
Components of net periodic cost
Service cost	$ 1,897,000	$ 1,872,000	5,693,000	5,614,000
Interest cost	2,836,000	2,549,000	8,507,000	7,649,000
Expected return on plan assets	(5,029,000)	(4,272,000)	(15,088,000)	(12,817,000)
Recognized actuarial loss	1,820,000	1,747,000	5,461,000	5,239,000
Prior service cost amortization	28,000	28,000	83,000	83,000
Net periodic benefit cost	1,552,000	1,924,000	4,656,000	5,768,000
OPEB [Member]
Components of net periodic cost
Service cost	1,130,000	1,063,000	3,391,000	3,190,000
Interest cost	1,564,000	1,434,000	4,692,000	4,304,000
Expected return on plan assets	(1,211,000)	(1,245,000)	(3,633,000)	(3,733,000)
Recognized actuarial loss	819,000	737,000	2,456,000	2,208,000
Prior service cost amortization	(91,000)	(91,000)	(273,000)	(273,000)
Net periodic benefit cost	$ 2,211,000	$ 1,898,000	$ 6,633,000	$ 5,696,000